Re: [PATCH] f2fs: fix wrong sum_page pointer in f2fs_gc

[Chao Yu <yuchao0@huawei.com>]

Hi Jaegeuk,

On 2016/10/13 7:23, Jaegeuk Kim wrote:
> This patch fixes using a wrong pointer for sum_page in f2fs_gc.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/gc.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index e48142f..9c18917 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -854,16 +854,16 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
>  
>  	for (segno = start_segno; segno < end_segno; segno++) {
>  
> -		if (get_valid_blocks(sbi, segno, 1) == 0 ||
> -					unlikely(f2fs_cp_error(sbi)))
> -			goto next;
> -
>  		/* find segment summary of victim */
>  		sum_page = find_get_page(META_MAPPING(sbi),
>  					GET_SUM_BLOCK(sbi, segno));
> -		f2fs_bug_on(sbi, !PageUptodate(sum_page));
>  		f2fs_put_page(sum_page, 0);
>  
> +		if (get_valid_blocks(sbi, segno, 1) == 0 ||
> +				!PageUptodate(sum_page) ||

Why uptodate flag of summary page can be cleared? someone truncates it?

Thanks,

> +				unlikely(f2fs_cp_error(sbi)))
> +			goto next;
> +
>  		sum = page_address(sum_page);
>  		f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
>  
>